The eco-epidemiology of Triatoma infestans in the temperate Monte Desert ecoregion of mid-western Argentina

BACKGROUND The eco-epidemiological status of Chagas disease in the Monte Desert ecoregion of western Argentina is largely unknown. We investigated the environmental and socio-demographic determinants of house infestation with Triatoma infestans, bug abundance, vector infection with Trypanosoma cruzi and host-feeding sources in a well-defined rural area of Lavalle Department in the Mendoza province. METHODS Technical personnel inspected 198 houses for evidence of infestation with T. infestans, and the 76 houses included in the current study were re-inspected. In parallel with the vector survey, an environmental and socio-demographic survey was also conducted. Univariate risk factor analysis for domiciliary infestation was carried out using Firth penalised logistic regression. We fitted generalised linear models for house infestation and bug abundance. Blood meals were tested with a direct ELISA assay, and T. cruzi infection was determined using a hot-start polymerase chain reaction (PCR) targeting the kinetoplast minicircle (kDNA-PCR). FINDINGS The households studied included an aged population living in precarious houses whose main economic activities included goat husbandry. T. infestans was found in 21.2% of 198 houses and in 55.3% of the 76 re-inspected houses. Peridomestic habitats exhibited higher infestation rates and bug abundances than did domiciles, and goat corrals showed high levels of infestation. The main host-feeding sources were goats. Vector infection was present in 10.2% of domiciles and 3.2% of peridomiciles. Generalised linear models showed that peridomestic infestation was positively and significantly associated with the presence of mud walls and the abundance of chickens and goats, and bug abundance increased with the number of all hosts except rabbits. MAIN CONCLUSIONS We highlight the relative importance of specific peridomestic structures (i.e., goat corrals and chicken coops) associated with construction materials and host abundance as sources of persistent bug infestation driving domestic colonisation. Environmental management strategies framed in a community-based programme combined with improved insecticide spraying and sustained vector surveillance are needed to effectively suppress local T. infestans populations.

The eco-epidemiology of Triatoma infestans in the temperate Monte Desert ecoregion of mid-western Argentina.

BACKGROUND: The eco-epidemiological status of Chagas disease in the Monte Desert ecoregion of western Argentina is largely unknown. We investigated the environmental and socio-demographic determinants of house infestation with Triatoma infestans, bug abundance, vector infection with Trypanosoma cruzi and host-feeding sources in a well-defined rural area of Lavalle Department in the Mendoza province. METHODS: Technical personnel inspected 198 houses for evidence of infestation with T. infestans, and the 76 houses included in the current study were re-inspected. In parallel with the vector survey, an environmental and socio-demographic survey was also conducted. Univariate risk factor analysis for domiciliary infestation was carried out using Firth penalised logistic regression. We fitted generalised linear models for house infestation and bug abundance. Blood meals were tested with a direct ELISA assay, and T. cruzi infection was determined using a hot-start polymerase chain reaction (PCR) targeting the kinetoplast minicircle (kDNA-PCR). FINDINGS: The households studied included an aged population living in precarious houses whose main economic activities included goat husbandry. T. infestans was found in 21.2% of 198 houses and in 55.3% of the 76 re-inspected houses. Peridomestic habitats exhibited higher infestation rates and bug abundances than did domiciles, and goat corrals showed high levels of infestation. The main host-feeding sources were goats. Vector infection was present in 10.2% of domiciles and 3.2% of peridomiciles. Generalised linear models showed that peridomestic infestation was positively and significantly associated with the presence of mud walls and the abundance of chickens and goats, and bug abundance increased with the number of all hosts except rabbits. MAIN CONCLUSIONS: We highlight the relative importance of specific peridomestic structures (i.e., goat corrals and chicken coops) associated with construction materials and host abundance as sources of persistent bug infestation driving domestic colonisation. Environmental management strategies framed in a community-based programme combined with improved insecticide spraying and sustained vector surveillance are needed to effectively suppress local T. infestans populations.

[Strategy to improve access to etiological treatment of Chagas disease at the first level of care in Argentina]. / Estrategia para mejorar el acceso al tratamiento etiológico para la enfermedad de Chagas en el primer nivel de atención en Argentina.

OBJECTIVE: Improve distribution of etiological treatment of Chagas disease by identifying barriers to the decentralization of treatment to the first level of care in Argentina. METHODS: A qualitative, exploratory, and descriptive study was conducted using semi-structured interviews of key actors belonging to the National Chagas Program and members of health teams at the first level of care, for the purpose of identifying barriers to diagnosis and treatment of Chagas disease at different levels (administrative, health agents, and community) that could affect a decentralized distribution strategy. Additionally, pilot decentralization was instituted in 10 primary health care centers in an Argentine province. RESULTS: Semi-structured interviews were conducted with 22 program heads and health professionals. Principal obstacles found were lack of systematic case-finding, poor coordination among levels of care and health system actors, lack of health team training on treatment, patient monitoring, and patient-related barriers. A pilot decentralization program was carried out and strategies were evaluated to optimize large-scale intervention. CONCLUSIONS: The results made it possible to improve implementation of the plan to decentralize treatment through better inter-program coordination, capitalization on existing monitoring and communication tools, and sensitization of health teams. Furthermore, recommendations were developed to improve diagnosis and treatment of Chagas disease.

Estrategia para mejorar el acceso al tratamiento etiológico para la enfermedad de Chagas en el primer nivel de atención en Argentina / Strategy to improve access to etiological treatment of Chagas disease at the first level of care in Argentina

Objetivo. Mejorar la distribución del tratamiento etiológico para la enfermedad de Chagas mediante la identificación de barreras para su descentralización al primer nivel de atención en Argentina. Métodos. Se llevó a cabo un estudio cualitativo, de carácter exploratorio y descriptivo, en base a entrevistas semiestructuradas a actores clave pertenecientes al Programa Nacional de Chagas y miembros de los equipos de salud del primer nivel de atención con el objetivo de identificar barreras para el diagnóstico y tratamiento de la enfermedad de Chagas en diferentes niveles (administrativo, efectores de salud y comunidad) que podrían afectar una estrategia descentralizada de distribución. Además, se implementó un piloto de descentralización en diez centros de atención primaria en una provincia argentina. Resultados. Se realizaron 22 entrevistas semiestructuradas con responsables de programas y profesionales de la salud. Los principales obstáculos hallados fueron la falta de búsqueda sistemática de casos, la poca articulación entre los niveles de atención y los actores del sistema de salud, la falta de capacitación del equipo de salud respecto al tratamiento, el seguimiento de los pacientes y las barreras asociadas a los pacientes. Se llevó a cabo un programa piloto de descentralización y se evaluaron estrategias para optimizar la intervención a gran escala. Conclusiones. Los resultados permitieron mejorar la implementación del plan de descentralización del tratamiento a través de una mejor articulación interprogramática, la capitalización de herramientas de monitoreo y de comunicación ya existentes, y la sensibilización de los equipos de salud. Además, se formularon recomendaciones tendientes a mejorar el diagnóstico y el tratamiento de la enfermedad de Chagas.

Objective. Improve distribution of etiological treatment of Chagas disease by identifying barriers to the decentralization of treatment to the first level of care in Argentina. Methods. A qualitative, exploratory, and descriptive study was conducted using semi-structured interviews of key actors belonging to the National Chagas Program and members of health teams at the first level of care, for the purpose of identifying barriers to diagnosis and treatment of Chagas disease at different levels (administrative, health agents, and community) that could affect a decentralized distribution strategy. Additionally, pilot decentralization was instituted in 10 primary health care centers in an Argentine province. Results. Semi-structured interviews were conducted with 22 program heads and health professionals. Principal obstacles found were lack of systematic case-finding, poor coordination among levels of care and health system actors, lack of health team training on treatment, patient monitoring, and patient-related barriers. A pilot decentralization program was carried out and strategies were evaluated to optimize large-scale intervention. Conclusions. The results made it possible to improve implementation of the plan to decentralize treatment through better inter-program coordination, capitalization on existing monitoring and communication tools, and sensitization of health teams. Furthermore, recommendations were developed to improve diagnosis and treatment of Chagas disease.

A motorized vehicle-mounted sprayer as a new tool for Chagas disease vector control.

Residual insecticide spraying still is the main tool used to suppress house infestations with Chagas disease vectors. While manual compression sprayers (MCS) have traditionally been used in Latin America, Mendoza's vector control program from Argentina introduced the use of a modified motorized vehicle-mounted sprayer (VMS) with apparent advantages over MCS. We conducted a randomized intervention trial to evaluate the effectiveness and selected components of the performance of MCS and VMS. We assessed house infestation by Triatoma infestans in 76 previously-infested houses at 0, 1, 4 and 12 months postintervention. Infestations were reduced substantially, with no significant differences between treatments. End-point infestations were restricted to peridomiciles. Although VMS required less time to complete the house spraying than MCS, both treatments had similar performance and did not suppress infestations completely. The main relative advantages of VMS were a reduced physical effort, especially under harsh field conditions, and potential gains in spray coverage per unit of time.

A motorized vehicle-mounted sprayer as a new tool for Chagas disease vector control / Equipamiento aspersor montado en vehículos como nueva herramienta para el control vectorial de la enfermedad de Chagas / Equipamento aspersor montado em veículo como ferramenta nova para o controle vetorial da doença de Chagas

Abstract: Residual insecticide spraying still is the main tool used to suppress house infestations with Chagas disease vectors. While manual compression sprayers (MCS) have traditionally been used in Latin America, Mendoza's vector control program from Argentina introduced the use of a modified motorized vehicle-mounted sprayer (VMS) with apparent advantages over MCS. We conducted a randomized intervention trial to evaluate the effectiveness and selected components of the performance of MCS and VMS. We assessed house infestation by Triatoma infestans in 76 previously-infested houses at 0, 1, 4 and 12 months postintervention. Infestations were reduced substantially, with no significant differences between treatments. End-point infestations were restricted to peridomiciles. Although VMS required less time to complete the house spraying than MCS, both treatments had similar performance and did not suppress infestations completely. The main relative advantages of VMS were a reduced physical effort, especially under harsh field conditions, and potential gains in spray coverage per unit of time.

Resumen: El empleo de insecticida residual es todavía la principal herramienta para suprimir la infestación domiciliaria por triatominos, vectores de la enfermedad de Chagas. Mientras los aspersores manuales activados por compresión han sido utilizados tradicionalmente en América Latina, el programa de control vectorial de la provincia de Mendoza, Argentina, introdujo el uso de un equipamiento aspersor montado en un vehículo, aparentemente con ventajas respecto al aspersor manual. Realizamos un ensayo de intervención aleatorizado para evaluar la efectividad y los componentes seleccionados del desempeño de los dos equipamientos. Evaluamos la infestación por Triatoma infestans en 76 vivendas, previamente infestados a 0, 1, 4 y 12 meses tras la intervención. Las infestaciones se redujeron substancialmente, sin diferencia significativa entre las dos técnicas. Las infestaciones finales se limitaban al peridomicilio. El equipamiento montado en el vehículo llevaba menos tiempo para completar la aplicación, comparado con el equipamiento manual, pero los dos tratamientos tuvieron un desempeño semejante y dejaron de suprimir completamente las infestaciones. Las principales ventajas del equipamiento montado en vehículo fueron: la reducción del esfuerzo físico, principalmente en condiciones adversas en el campo, y potenciales beneficios en términos de cobertura de pulverización por unidad de tiempo.

Resumo: A aplicação de inseticida residual ainda é a principal medida para suprimir a infestação domiciliar por triatomíneos, vetores da doença de Chagas. Enquanto os aspersores manuais acionados por compressão têm sido utilizados tradicionalmente na América Latina, o programa de controle vetorial da Província de Mendoza, Argentina, introduziu o uso de um equipamento aspersor montado em veículo, aparentemente com vantagem em relação ao aspersor manual. Realizamos um estudo randomizado de intervenção para avaliar a efetividade e os componentes selecionados do desempenho dos dois equipamentos. Avaliamos a infestação por Triatoma infestans em 76 domicílios previamente infestados a 0, 1, 4 e 12 meses pós-intervenção. As infestações foram reduzidas substancialmente, sem diferença significativa entre as duas técnicas. As infestações finais eram limitadas ao peridomicílio. O equipamento montado em veículo levava menos tempo para completar a aplicação, comparado com o equipamento manual, mas os dois tratamentos tiveram desempenho semelhante e deixaram de suprimir completamente as infestações. As principais vantagens do equipamento montado em veículo foram redução do esforço físico, principalmente em condições adversas em campo, e potenciais ganhos em termos de cobertura de borrifação por unidade de tempo.

Estrategia para mejorar el acceso al tratamiento etiológico para la enfermedad de Chagas en el primer nivel de atención en Argentina / Strategy to improve access to etiological treatment of Chagas disease at the first level of care in Argentina

RESUMEN Objetivo Mejorar la distribución del tratamiento etiológico para la enfermedad de Chagas mediante la identificación de barreras para su descentralización al primer nivel de atención en Argentina. Métodos Se llevó a cabo un estudio cualitativo, de carácter exploratorio y descriptivo, en base a entrevistas semiestructuradas a actores clave pertenecientes al Programa Nacional de Chagas y miembros de los equipos de salud del primer nivel de atención con el objetivo de identificar barreras para el diagnóstico y tratamiento de la enfermedad de Chagas en diferentes niveles (administrativo, efectores de salud y comunidad) que podrían afectar una estrategia descentralizada de distribución. Además, se implementó un piloto de descentralización en diez centros de atención primaria en una provincia argentina. Resultados Se realizaron 22 entrevistas semiestructuradas con responsables de programas y profesionales de la salud. Los principales obstáculos hallados fueron la falta de búsqueda sistemática de casos, la poca articulación entre los niveles de atención y los actores del sistema de salud, la falta de capacitación del equipo de salud respecto al tratamiento, el seguimiento de los pacientes y las barreras asociadas a los pacientes. Se llevó a cabo un programa piloto de descentralización y se evaluaron estrategias para optimizar la intervención a gran escala. Conclusiones Los resultados permitieron mejorar la implementación del plan de descentralización del tratamiento a través de una mejor articulación interprogramática, la capitalización de herramientas de monitoreo y de comunicación ya existentes, y la sensibilización de los equipos de salud. Además, se formularon recomendaciones tendientes a mejorar el diagnóstico y el tratamiento de la enfermedad de Chagas.

ABSTRACT Objective Improve distribution of etiological treatment of Chagas disease by identifying barriers to the decentralization of treatment to the first level of care in Argentina. Methods A qualitative, exploratory, and descriptive study was conducted using semi-structured interviews of key actors belonging to the National Chagas Program and members of health teams at the first level of care, for the purpose of identifying barriers to diagnosis and treatment of Chagas disease at different levels (administrative, health agents, and community) that could affect a decentralized distribution strategy. Additionally, pilot decentralization was instituted in 10 primary health care centers in an Argentine province. Results Semi-structured interviews were conducted with 22 program heads and health professionals. Principal obstacles found were lack of systematic case-finding, poor coordination among levels of care and health system actors, lack of health team training on treatment, patient monitoring, and patient-related barriers. A pilot decentralization program was carried out and strategies were evaluated to optimize large-scale intervention. Conclusions The results made it possible to improve implementation of the plan to decentralize treatment through better inter-program coordination, capitalization on existing monitoring and communication tools, and sensitization of health teams. Furthermore, recommendations were developed to improve diagnosis and treatment of Chagas disease.

Spatial heterogeneity and risk maps of community infestation by Triatoma infestans in rural northwestern Argentina.

BACKGROUND: Fifty years of residual insecticide spraying to control Triatoma infestans in the Gran Chaco region of northern Argentina, Paraguay and Bolivia shows that vertically coordinated interventions aiming at full coverage have limited effects and are unsustainable. We quantified the spatial distribution of T. infestans domestic infestation at the district level, identified environmental factors associated with high infestation and then explored the usefulness of risk maps for the spatial stratification of interventions. METHODS AND FINDINGS: We performed spatial analyses of house infestation data collected by the National Chagas Service in Moreno Department, northern Argentina (1999-2002). Clusters of high domestic infestation occurred in the southwestern extreme of the district. A multi-model selection approach showed that domestic infestation clustered in areas of low elevation, with few farmlands, high density of rural houses, high mean maximum land surface temperature, large NDVI, and high percentage of degraded and deforested lands. The best model classified 98.4% of the communities in the training dataset (sensitivity, 93.3%; specificity, 95.4%). The risk map evidenced that the high-risk area only encompassed 16% of the district. By building a network-based transportation model we assessed the operational costs of spatially contiguous and spatially targeted interventions. Targeting clusters of high infestation would have reached -80% of all communities slated for full-coverage insecticide spraying, reducing in half the total time and economic cost incurred by a spatially contiguous strategy. CONCLUSIONS AND SIGNIFICANCE: In disperse rural areas where control programs can accomplish limited coverage, consideration of infestation hot spots can contribute to the design and execution of cost-effective interventions against Chagas disease vectors. If field validated, targeted vertical control in high risk areas and horizontal control in medium to low risk areas may provide both a logistically and economically feasible alternative to blanket vertical insecticide spraying when resources are limited.

Cobertura de tratamiento etiológico para la infección por Trypanosoma cruzi, en niños menores de 15 años, en la república Argentina: período 2003-2006 / Coverage of etiological treatment for infection by Trypanosoma cruzi in children less than 15 years-old in Argentina: period 2003 – 2006

En el marco de las acciones del Programa Nacional de Chagas (PNCh), los criterios de atención del infectado chagásico contemplan la detección precoz de la infección por Trypanosoma cruzi e el tratamiento específico en la población infantil. El presente trabajo busca evaluar la cobertura detratamiento etiológico para Chagas en niños menores de 1 año -Chagas congénito- e entre 1 y 14 añosfase crónica recient durante el período 2003 al 2006. Los datos fueron aportados por los referentes de la Red de Laboratorios de Chagas provinciales e jefes de Programas Provinciales e Jurisdicciones Nacionales de Chagas de la República Argentina, a la Coordinación Nacional de Control de Vectores (CNCV). Se estudiaron 13.866 niños menores de 1 año, con métodos parasitológicos e/o duplasserológicas para la infección por T. cruzi, de los cuales fueron positivos 1.016 niños (7,33por cento) e se trataron 529 (52,07por cento). Por estudios serológicos poblacionales se analizaron 158.640 niños menores de 15 años, de áreas endémicas, se detectaron 4.549 niños positivos (2,87por cento) e se trataron 1.526 (33,55por cento). Del análisis global de los datos (grupos 1 e 2) se observa una heterogeneidad en la cobertura de tratamiento, entre las provincias, siendo en general inadecuada (menor al 50por cento)...

Evolución de la brecha entre el número de casos esperados y el notificado de chagas congénito para la Argentina, en el período 2002 - 2008 / Evolution of the gap between the number of expected cases and congenital chagas reported for Argentina in the period 2002 - 2008

La enfermedad de Chagas constituye un serio problema sanitario y social en gran parte del continente americano, siendo una de las causas de mayor morbimortalidad en América Latina. La vía de transmisión más importante es la vectorial, pero la transmisión vertical de Trypanosoma cruzi ha ido aumentando su importancia a medida que la transmisión vectorial y transfusional han sido crecientemente controladas. (...). O presente trabajo estimó, a través de un modelo matemático determinístico, la brecha entre el número de casos esperados y el conocido de Chagas congénito para provincias de Argentina, seleccionadas según grupo de riesgo de transmisión vectorial, en el período 2002 – 2008 y se comparó con el valor hallado para el período 1994 - 2001. Para estimar estas brechas fueron definidos 2 escenarios teniendo en cuenta dos variables, una vectorial, definida por lo que estimamos mejor representaba el estado de control de las provincias y la segunda variable definida por el porcentaje de cobertura de tratamiento médico específico. Según nuestro modelo la brecha disminuyó marcadamente respecto al total para el país en 1994-2001, con una relación de 1, 9:1 y 1, 6:1 para los escenarios 1 y 2 respectivamente, versus el 6,3:1 para el país en el período anterior...

Chagas disease is a severe social and health problem in most part of the American continent, and one of the leading causes of morbidity and mortality in Latin America. Although vectorial transmission is still the most important route, vertical transmission is gaining importance as control strategies are increasingly implemented against vectorial and transfusion transmission. Vertical transmission rates vary widely between countries and geographical areas, varying from 0.7-4% in Argentina, 10.5% in Paraguay, to 21% in Bolivia. Using a mathematical model, this thesis aimed at estimating the lag between the expected and observed number of congenital Chagas cases in a six Argentinian provinces, chiosen according to their level of vector transmission. The estimation is carried out for the period 2002 – 2008 and compared to 1994-2001. For each province, scenarios were build considering different levels of vector control activity and treatment coverage. According to the model, we concluded that the sub-notification of congenital Chagas has decreased in Argentina when compared to the 1994-2001 period, with an estimated ratio of 1.9:1 and 1.6:1 in 2002 – 2008, versus 6.3:1 in 1994-2001 (the latter was taken from the literature). Moreover, we found that the sub notification was greater in provinces with high vectorial transmission than in provinces with low vectorial transmission...

Cost-effectiveness of chagas disease vector control strategies in Northwestern Argentina.

BACKGROUND: Control and prevention of Chagas disease rely mostly on residual spraying of insecticides. In Argentina, vector control shifted from a vertical to a fully horizontal strategy based on community participation between 1992 and 2004. The effects of such strategy on Triatoma infestans, the main domestic vector, and on disease transmission have not been assessed. METHODS AND FINDINGS: Based on retrospective (1993-2004) records from the Argentinean Ministry of Health for the Moreno Department, Northwestern Argentina, we performed a cost-effectiveness (CE) analysis and compared the observed CE of the fully horizontal vector control strategy with the expected CE for a vertical or a mixed (i.e., vertical attack phase followed by horizontal surveillance) strategy. Total direct costs (in 2004 US$) of the horizontal and mixed strategies were, respectively, 3.3 and 1.7 times lower than the costs of the vertical strategy, due to reductions in personnel costs. The estimated CE ratios for the vertical, mixed and horizontal strategies were US$132, US$82 and US$45 per averted human case, respectively. When per diems were excluded from the costs (i.e., simulating the decentralization of control activities), the CE of vertical, mixed and horizontal strategies was reduced to US$60, US$42 and US$32 per averted case, respectively. CONCLUSIONS AND SIGNIFICANCE: The mixed strategy would have averted between 1.6 and 4.0 times more human cases than the fully horizontal strategy, and would have been the most cost-effective option to interrupt parasite transmission in the Department. In rural and dispersed areas where waning vertical vector programs cannot accomplish full insecticide coverage, alternative strategies need to be developed. If properly implemented, community participation represents not only the most appealing but also the most cost-effective alternative to accomplish such objectives.

Control de Chagas en la Argentina: su evolución / Chagass disease control in Argentina: the evolution

En 1952 se creó el Servicio Nacional de Profilaxis y Lucha contra la Enfermedad de Chagas para investigar la incidencia, conocer los índices de infestación por triatominos y propender a su eliminación. Desde 1962 trabaja el Laboratorio de Diagnóstico de Chagas, que a partir de 1973 se denomina Instituto Nacional de Diagnóstico e Investigación de la Enfermedad de Chagas Dr. Mario Fatala Chabén. En 1972 el Programa de Control incorpora un total de 19 provincias endémicas con una estrategia vertical, con lo que logra un impacto manifiesto pero sin continuidad ni contig³idad por dificultades administrativas, financieras y logísticas, por lo que difícilmente se llegaba a la fase de vigilancia y vastas zonas se reinfestaban. En 1991, la Comisión Intergubernamental contra la Enfermedad de Chagas, integrada por la Argentina, Brasil, Chile, Paraguay y Uruguay elabora un programa y un Plan de Acción Subregional para eliminar el T. infestans domiciliario e interrumpir la transmisión de T. cruzi por transfusión. En la Argentina se implementa mediante el "Programa Ramón Carrillo" con los siguientes objetivos: desinsectación de todas las viviendas del área endémica; instalación de la vigilancia con participación comunitaria y a través de múltiples efectores; detección de infección chagásica de todos los niños menores de 15 años residentes en áreas endémicas y bajo vigilancia; atención médica y tratamiento supervisado de los infectados por T. Cruzi; control de la madre chagásica y su hijo hasta el año de vida; control de laboratorio y bancos de sangre y control de dadores y receptores de trasplantes de órganos. Durante el período 1993-2003 se completó el 98 por ciento (927741 viviendas) de la meta de desinsectación en áreas de ataque y se instaló la vigilancia a través de diferentes efectores, que abarcó una cobertura superior al 87 por ciento. En 1992 se desarrolló el subprograma "Grandes Maternidades" para Diagnóstico y Tratamiento para Chagas congénito. En 1999, la probabilidad media de transmisión para el período fue del 4,88 por ciento. La tasa de infestación intradomiciliaria en áreas bajo vigilancia o recientemente instalada disminuyó en el período 1992-2003 del 6,11 por ciento al 0,95 por ciento. La seroprevalencia en niños menores de 15 años de áreas rurales en el período 1992-2003 disminuyó del 6,3 por ciento al 2,74 por ciento. En embarazadas disminuyó del 11,84 por ciento al 5,49 por ciento en el período 1994/95-2003. La situación actual de ... (AU)

Control de Chagas en la Argentina: su evolución / Chagas's disease control in Argentina: the evolution

En 1952 se creó el Servicio Nacional de Profilaxis y Lucha contra la Enfermedad de Chagas para investigar la incidencia, conocer los índices de infestación por triatominos y propender a su eliminación. Desde 1962 trabaja el Laboratorio de Diagnóstico de Chagas, que a partir de 1973 se denomina Instituto Nacional de Diagnóstico e Investigación de la Enfermedad de Chagas Dr. Mario Fatala Chabén. En 1972 el Programa de Control incorpora un total de 19 provincias endémicas con una estrategia vertical, con lo que logra un impacto manifiesto pero sin continuidad ni contigüidad por dificultades administrativas, financieras y logísticas, por lo que difícilmente se llegaba a la fase de vigilancia y vastas zonas se reinfestaban. En 1991, la Comisión Intergubernamental contra la Enfermedad de Chagas, integrada por la Argentina, Brasil, Chile, Paraguay y Uruguay elabora un programa y un Plan de Acción Subregional para eliminar el T. infestans domiciliario e interrumpir la transmisión de T. cruzi por transfusión. En la Argentina se implementa mediante el "Programa Ramón Carrillo" con los siguientes objetivos: desinsectación de todas las viviendas del área endémica; instalación de la vigilancia con participación comunitaria y a través de múltiples efectores; detección de infección chagásica de todos los niños menores de 15 años residentes en áreas endémicas y bajo vigilancia; atención médica y tratamiento supervisado de los infectados por T. Cruzi; control de la madre chagásica y su hijo hasta el año de vida; control de laboratorio y bancos de sangre y control de dadores y receptores de trasplantes de órganos. Durante el período 1993-2003 se completó el 98 por ciento (927741 viviendas) de la meta de desinsectación en áreas de ataque y se instaló la vigilancia a través de diferentes efectores, que abarcó una cobertura superior al 87 por ciento. En 1992 se desarrolló el subprograma "Grandes Maternidades" para Diagnóstico y Tratamiento para Chagas congénito. En 1999, la probabilidad media de transmisión para el período fue del 4,88 por ciento. La tasa de infestación intradomiciliaria en áreas bajo vigilancia o recientemente instalada disminuyó en el período 1992-2003 del 6,11 por ciento al 0,95 por ciento. La seroprevalencia en niños menores de 15 años de áreas rurales en el período 1992-2003 disminuyó del 6,3 por ciento al 2,74 por ciento. En embarazadas disminuyó del 11,84 por ciento al 5,49 por ciento en el período 1994/95-2003. La situación actual de ...

Effectiveness of residual spraying of peridomestic ecotopes with deltamethrin and permethrin on Triatoma infestans in rural western Argentina: a district-wide randomized trial.

OBJECTIVE: To compare the effectiveness of a single residual spraying of pyrethroids on the occurrence and abundance of Triatoma infestans in peridomestic ecotopes in rural La Rioja. METHODS: A total of 667 (32.8%) peridomestic sites positive for T. infestans in May 1999 were randomly assigned to treatment within each village, sprayed in December 1999, and reinspected in December 2000. Treatments included 2.5% suspension concentrate (SC) deltamethrin in water at 25 mg active ingredient (a.i.)/m(2) applied with: (a) manual compression sprayers (standard treatment) or (b) power sprayers; (c) 1.5% emulsifiable concentrate (EC) deltamethrin at 25 mg a.i./m(2); and (d) 10% EC cis-permethrin at 170 mg a.i./m(2). EC pyrethroids were diluted in soybean oil and applied with power sprayers. All habitations were sprayed with the standard treatment. FINDINGS: The prevalence of T. infestans 1-year post-spraying was significantly lower in sites treated with SC deltamethrin applied with manual (24%) or power sprayers (31%) than in sites treated with EC deltamethrin (40%) or EC permethrin (53%). The relative odds of infestation and catch of T. infestans 1-year post-spraying significantly increased with the use of EC pyrethroids, the abundance of bugs per site before spraying, total surface, and host numbers. All insecticides had poor residual effects on wooden posts. CONCLUSION: Most of the infestations probably originated from triatomines that survived exposure to insecticides at each site. Despite the standard treatment proving to be the most effective, the current tactics and procedures fail to eliminate peridomestic populations of T. infestans in semiarid rural areas and need to be revised.

Prevalencia de factores de riesgo cardiovascular en ingresantes universitarios / Prevalence of cardiovascular risk factors in first year university students

Com o objetivo de conhecer a prevalência de fatores de risco para doenças cárdio-vasculares (ECV) e sua relaçäo com antecedentes familiares de doença, estudaram-se 3.357 ingressantes ao primeiro ano da Universidade de Mar del Plata, no ano de 1991, que completaram seu exame médico obrigatório. A prevalência de antecedentes familiares de hipercolesterolemia, hipertensäo, diabetes mellitus, obesidade, doenças cárdio-vasculares foi de 27,5 por cento, 42,1 por cento, 26,9 por cento, 27,2 por cento e 42,1 por cento, respectivamente. Orienta por cento dos alunos reportaram, ao menos, um dos antecedentes familiares estudados. A prevalência de hipertensäo (pressäo arterial sistólica > 140 mmhg e/ou pressäo arterial diastólica > ou = 90 mmhg) e de hipercolesterolemia (> ou = 210 mg/dl), nos participantes, foi de 7,0 por cento e 14,4 por cento. Observaram-se associaçöes de hipertensäo com índice de massa corporal (IMC), sexo masculino e idade. A prevalência do hábito de fumar foi de 27,1 por cento, näo apresentando diferenças entre sexos. O hábito correlacionou-se positivamente com idade e observaram-se diferentes prevalências segundo a carreira escolhida. A presença de colesterolemia aumentada correlacionou-se com a idade. O IMC e os antecedentes familiares de obesidade (OR=1,32 IC 95 por cento = 1,06 a 1,64) e hipercolesterolemia (OR=1,38 IC 95 por cento = 1,10-1,69). Detectaram-se 3,7 por cento anormalidades no aparelho cardiovascular. Observou-se associacäo com antecedentes de doença cardíaca familiar. A prevalência de fatores de risco-vasculares representa uma advertência, dada a juventude da populaçäo considerada, e mostra a necessidade de insistir em medidas educativas e de promoçäo de condutas preventivas